From patchwork Wed Nov 10 13:19:59 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arun Bharadwaj X-Patchwork-Id: 70638 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id A16C9B70E7 for ; Thu, 11 Nov 2010 00:31:45 +1100 (EST) Received: from localhost ([127.0.0.1]:50762 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PGAm4-0002zM-IQ for incoming@patchwork.ozlabs.org; Wed, 10 Nov 2010 08:31:40 -0500 Received: from [140.186.70.92] (port=49444 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PGAau-00040E-KR for qemu-devel@nongnu.org; Wed, 10 Nov 2010 08:20:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PGAas-0004x4-0a for qemu-devel@nongnu.org; Wed, 10 Nov 2010 08:20:07 -0500 Received: from e28smtp06.in.ibm.com ([122.248.162.6]:50012) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PGAaq-0004wm-RT for qemu-devel@nongnu.org; Wed, 10 Nov 2010 08:20:05 -0500 Received: from d28relay05.in.ibm.com (d28relay05.in.ibm.com [9.184.220.62]) by e28smtp06.in.ibm.com (8.14.4/8.13.1) with ESMTP id oAADK1uK014546 for ; Wed, 10 Nov 2010 18:50:01 +0530 Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay05.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id oAADK05G721128 for ; Wed, 10 Nov 2010 18:50:01 +0530 Received: from d28av05.in.ibm.com (loopback [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id oAADK0Ii014385 for ; Thu, 11 Nov 2010 00:20:00 +1100 Received: from localhost6.localdomain6 (Crystal-Planet.in.ibm.com [9.124.35.43]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id oAADK0DJ014375 for ; Thu, 11 Nov 2010 00:20:00 +1100 To: qemu-devel@nongnu.org From: Arun R Bharadwaj Date: Wed, 10 Nov 2010 18:49:59 +0530 Message-ID: <20101110131959.29714.51621.stgit@localhost6.localdomain6> In-Reply-To: <20101110131822.29714.34137.stgit@localhost6.localdomain6> References: <20101110131822.29714.34137.stgit@localhost6.localdomain6> User-Agent: StGit/0.15 MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) Subject: [Qemu-devel] [PATCH 3/3] Add helper functions to enable virtio-9p make use of the threadlets X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Gautham R Shenoy infrastructure for offloading blocking tasks such as making posix calls on to the helper threads and handle the post_posix_operations() from the context of the iothread. This frees the vcpu thread to process any other guest operations while the processing of v9fs_io is in progress. Signed-off-by: Gautham R Shenoy Signed-off-by: Sripathi Kodi Signed-off-by: Arun R Bharadwaj --- hw/virtio-9p.c | 164 ++++++++++++++++++++++++++++++++++++++++++++++++++++ posix-aio-compat.c | 30 +++------- qemu-threadlets.c | 21 +++++++ qemu-threadlets.h | 1 vl.c | 3 + 5 files changed, 196 insertions(+), 23 deletions(-) diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c index 7c59988..1ada57b 100644 --- a/hw/virtio-9p.c +++ b/hw/virtio-9p.c @@ -18,6 +18,7 @@ #include "fsdev/qemu-fsdev.h" #include "virtio-9p-debug.h" #include "virtio-9p-xattr.h" +#include "qemu-threadlets.h" int debug_9p_pdu; @@ -33,6 +34,149 @@ enum { Oappend = 0x80, }; +typedef struct V9fsPostOp { + QTAILQ_ENTRY(V9fsPostOp) node; + void (*func)(void *arg); + void *arg; +} V9fsPostOp; + +static struct { + int rfd; + int wfd; + QemuMutex lock; + QTAILQ_HEAD(, V9fsPostOp) post_op_list; +} v9fs_async_struct; + +static void die2(int err, const char *what) +{ + fprintf(stderr, "%s failed: %s\n", what, strerror(err)); + abort(); +} + +static void die(const char *what) +{ + die2(errno, what); +} + +#define ASYNC_MAX_PROCESS 5 + +/** + * v9fs_process_post_ops: Process any pending v9fs_post_posix_operation + * @arg: Not used. + * + * This function serves as a callback to the iothread to be called into whenever + * the v9fs_async_struct.wfd is written into. This thread goes through the list + * of v9fs_post_posix_operations() and executes them. In the process, it might + * queue more job on the asynchronous thread pool. + */ +static void v9fs_process_post_ops(void *arg) +{ + int count = 0; + struct V9fsPostOp *post_op; + int ret; + char byte; + + qemu_mutex_lock(&v9fs_async_struct.lock); + do { + ret = read(v9fs_async_struct.rfd, &byte, sizeof(byte)); + } while (ret > 1 || (ret == -1 && errno == EINTR)); + + for (count = 0; count < ASYNC_MAX_PROCESS; count++) { + if (QTAILQ_EMPTY(&(v9fs_async_struct.post_op_list))) { + break; + } + post_op = QTAILQ_FIRST(&(v9fs_async_struct.post_op_list)); + QTAILQ_REMOVE(&(v9fs_async_struct.post_op_list), post_op, node); + + qemu_mutex_unlock(&v9fs_async_struct.lock); + post_op->func(post_op->arg); + qemu_free(post_op); + qemu_mutex_lock(&v9fs_async_struct.lock); + } + qemu_mutex_unlock(&v9fs_async_struct.lock); +} + +/** + * v9fs_async_signal: Inform the io-thread of completion of async job. + * + * This function is used to inform the iothread that a particular + * async-operation pertaining to v9fs has been completed and that the io thread + * can handle the v9fs_post_posix_operation. + * + * This is based on the aio_signal_handler + */ +static inline void v9fs_async_signal(void) +{ + char byte = 0; + ssize_t ret; + int tries = 0; + + qemu_mutex_lock(&v9fs_async_struct.lock); + do { + assert(tries != 100); + ret = write(v9fs_async_struct.wfd, &byte, sizeof(byte)); + tries++; + } while (ret < 0 && errno == EAGAIN); + qemu_mutex_unlock(&v9fs_async_struct.lock); + + if (ret < 0 && errno != EAGAIN) { + die("write() in v9fs"); + } + + if (kill(getpid(), SIGUSR2)) { + die("kill failed"); + } +} + +/** + * v9fs_async_helper_done: Marks the completion of the v9fs_async job + * @func: v9fs_post_posix_func() for post-processing invoked in the context of + * the io-thread + * @arg: Argument to func. + * + * This function is called from the context of one of the asynchronous threads + * in the thread pool. This is called when the asynchronous thread has finished + * executing a v9fs_posix_operation. It's purpose is to initiate the process of + * informing the io-thread that the v9fs_posix_operation has completed. + */ +static void v9fs_async_helper_done(void (*func)(void *arg), void *arg) +{ + struct V9fsPostOp *post_op; + + post_op = qemu_mallocz(sizeof(*post_op)); + post_op->func = func; + post_op->arg = arg; + + qemu_mutex_lock(&v9fs_async_struct.lock); + QTAILQ_INSERT_TAIL(&(v9fs_async_struct.post_op_list), post_op, node); + qemu_mutex_unlock(&v9fs_async_struct.lock); + + v9fs_async_signal(); +} + +/** + * v9fs_do_async_posix: Offload v9fs_posix_operation onto async thread. + * @vs: V9fsOPState variable for the OP operation. + * @posix_fn: The posix function which has to be offloaded onto async thread. + * @post_fn_ptr: Address of the location to hold the post_fn corresponding to + * the posix_fn + * @post_fn: The post processing function corresponding to the posix_fn. + * + * This function is a helper to offload posix_operation on to the asynchronous + * thread pool. It sets up the associations with the post_function that needs to + * be invoked by from the context of the iothread once the posix_fn has been + * executed. + */ +static void v9fs_do_async_posix(ThreadletWork *work , + void (*posix_fn)(ThreadletWork *work), + void (**post_fn_ptr)(void *arg), + void (*post_fn)(void *arg)) +{ + *post_fn_ptr = post_fn; + work->func = posix_fn; + submit_work(work); +} + static int omode_to_uflags(int8_t mode) { int ret = 0; @@ -3657,7 +3801,7 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf) int i, len; struct stat stat; FsTypeEntry *fse; - + int fds[2]; s = (V9fsState *)virtio_common_init("virtio-9p", VIRTIO_ID_9P, @@ -3740,5 +3884,23 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf) s->tag_len; s->vdev.get_config = virtio_9p_get_config; + if (qemu_pipe(fds) == -1) { + fprintf(stderr, "failed to create fd's for virtio-9p\n"); + exit(1); + } + + v9fs_async_struct.rfd = fds[0]; + v9fs_async_struct.wfd = fds[1]; + + fcntl(fds[0], F_SETFL, O_NONBLOCK); + fcntl(fds[1], F_SETFL, O_NONBLOCK); + + qemu_set_fd_handler(fds[0], v9fs_process_post_ops, NULL, NULL); + QTAILQ_INIT(&v9fs_async_struct.post_op_list); + qemu_mutex_init(&(v9fs_async_struct.lock)); + + (void)v9fs_do_async_posix; + (void)v9fs_async_helper_done; + return &s->vdev; } diff --git a/posix-aio-compat.c b/posix-aio-compat.c index b357449..515579f 100644 --- a/posix-aio-compat.c +++ b/posix-aio-compat.c @@ -260,11 +260,14 @@ static ssize_t handle_aiocb_rw(struct qemu_paiocb *aiocb) return nbytes; } +static PosixAioState *posix_aio_state; + static void aio_thread(ThreadletWork *work) { pid_t pid; struct qemu_paiocb *aiocb = container_of(work, struct qemu_paiocb, work); ssize_t ret = 0; + char byte = 0; pid = getpid(); @@ -289,6 +292,11 @@ static void aio_thread(ThreadletWork *work) aiocb->ret = ret; qemu_mutex_unlock(&aiocb_mutex); + ret = write(posix_aio_state->wfd, &byte, sizeof(byte)); + if (ret < 0 && errno != EAGAIN) { + die("write()"); + } + if (kill(pid, aiocb->ev_signo)) { die("kill failed"); } @@ -407,22 +415,6 @@ static int posix_aio_flush(void *opaque) return !!s->first_aio; } -static PosixAioState *posix_aio_state; - -static void aio_signal_handler(int signum) -{ - if (posix_aio_state) { - char byte = 0; - ssize_t ret; - - ret = write(posix_aio_state->wfd, &byte, sizeof(byte)); - if (ret < 0 && errno != EAGAIN) - die("write()"); - } - - qemu_service_io(); -} - static void paio_remove(struct qemu_paiocb *acb) { struct qemu_paiocb **pacb; @@ -518,7 +510,6 @@ BlockDriverAIOCB *paio_ioctl(BlockDriverState *bs, int fd, int paio_init(void) { - struct sigaction act; PosixAioState *s; int fds[2]; @@ -529,11 +520,6 @@ int paio_init(void) s = qemu_malloc(sizeof(PosixAioState)); - sigfillset(&act.sa_mask); - act.sa_flags = 0; /* do not restart syscalls to interrupt select() */ - act.sa_handler = aio_signal_handler; - sigaction(SIGUSR2, &act, NULL); - s->first_aio = NULL; if (qemu_pipe(fds) == -1) { fprintf(stderr, "failed to create pipe\n"); diff --git a/qemu-threadlets.c b/qemu-threadlets.c index 23b4ecf..1e78f56 100644 --- a/qemu-threadlets.c +++ b/qemu-threadlets.c @@ -16,12 +16,28 @@ #include "qemu-threadlets.h" #include "osdep.h" +#include #define MAX_GLOBAL_THREADS 64 #define MIN_GLOBAL_THREADS 8 static ThreadletQueue globalqueue; static int globalqueue_init; +static void threadlet_io_completion_signal_handler(int signum) +{ + qemu_service_io(); +} + +static void threadlet_register_signal_handler(void) +{ + struct sigaction act; + + sigfillset(&act.sa_mask); + act.sa_flags = 0; /* do not restart syscalls to interrupt select() */ + act.sa_handler = threadlet_io_completion_signal_handler; + sigaction(SIGUSR2, &act, NULL); +} + static void *threadlet_worker(void *data) { ThreadletQueue *queue = data; @@ -166,3 +182,8 @@ void threadlet_queue_init(ThreadletQueue *queue, qemu_mutex_init(&queue->lock); qemu_cond_init(&queue->cond); } + +void threadlet_init(void) +{ + threadlet_register_signal_handler(); +} diff --git a/qemu-threadlets.h b/qemu-threadlets.h index f869304..6f67a56 100644 --- a/qemu-threadlets.h +++ b/qemu-threadlets.h @@ -45,4 +45,5 @@ extern int dequeue_work_on_queue(ThreadletQueue *queue, extern int dequeue_work(ThreadletWork *work); extern void threadlet_queue_init(ThreadletQueue *queue, int max_threads, int min_threads); +extern void threadlet_init(void); #endif diff --git a/vl.c b/vl.c index df414ef..7b9a425 100644 --- a/vl.c +++ b/vl.c @@ -148,6 +148,7 @@ int main(int argc, char **argv) #include "qemu-config.h" #include "qemu-objects.h" #include "qemu-options.h" +#include "qemu-threadlets.h" #ifdef CONFIG_VIRTFS #include "fsdev/qemu-fsdev.h" #endif @@ -2922,6 +2923,8 @@ int main(int argc, char **argv, char **envp) exit(1); } + threadlet_init(); + /* init generic devices */ if (qemu_opts_foreach(qemu_find_opts("device"), device_init_func, NULL, 1) != 0) exit(1);